(1) Field of the Invention
The present invention relates to airborne imaging systems and, more particularly, to an automated airborne video recording system for imaging pipeline and electric line rights-of-way, or any other linear ground features.
(2) Description of Prior Art
Federal regulation requires that pipeline operators monitor their right of ways in an effort to prevent accidental damage to the pipeline and to detect leaks. As a result, major oil and natural gas pipeline companies each regularly monitor hundreds of thousands of miles of pipeline in the continental United States, and more on a multi-national scale. This is no small task. Conventional monitoring entails flying pilot/observers in light aircraft over the pipeline. The routine occurs usually at two week intervals. The aircraft flies at low altitude (500 ft to 1000 ft) and the pilot/observer visually inspects the right of way. Although this is a cost effective method of monitoring, it is not the most efficient. Advances in video and software technologies provide a good foundation for automation in this field. Indeed, this is beginning to occur.
Aerial video surveying of pipelines, electric lines, telecom corridors, railways, roadways and other linear ground features such as canals is already a viable option to visual surveying. U.S. Patent Application No. 2005023824 by Llamas et al. shows the automatic capture of detailed survey images using gimbaled cameras to aim at a linear infrastructure in an automatic way. It does this on the basis of 3D spatial position of a facility to be inspected.
F. Rafi et al. “Autonomous Target Following by Unmanned Aerial Vehicles”, SPIE Defense and Security Symposium 406, Orlando Fla. describes an function for the autonomous navigation of an unmanned aerial vehicle (UAV) in which the aircraft visually tracks the target using a mounted camera. The camera is controlled by the function according to the position and orientation of the aircraft and the position of the target.
U.S. Pat. No. 5,596,494 to Kuo issued Jan. 21, 1997 shows a method and apparatus for acquiring digital maps, wherein images of terrestrial scenes and the absolute geophysical coordinates (Latitude and Longitude) of ground objects are acquired simultaneously by an aircraft.
Japan Publication number JP10210457 by Nakagawa Masahiro (Mitsubishi Electric Corp) published 1998 Aug. 7 shows a system for directing a camera to automatically photograph and record from an aircraft without operation by an operator by previously inputting the photographing position. An arithmetic unit calculates the direction of a gimbal stand, based on position, azimuth, and photographing position coordinates.
U.S. Pat. No. 6,195,122 to Vincent issued Feb. 27, 2001 shows an image system that captures, along with the images, information defining both the position and the orientation of a camera along with the distance to the subject.
U.S. Pat. No. 4,700,307 to Mons et al. issued Oct. 13, 1987 (General Dynamics) shows a method of navigating an airborne vehicle using observation of linear features such as roads, railroads, rivers or the like. Maps of linear features in several discrete areas along an intended flight path are prepared and entered into an on-board computer memory. The vehicle typically uses an inertial navigation system during flight from the origin to the first mapped area. Imaging sensors and on-board processing detect linear features as the vehicle approaches or passes over them.
U.S. Pat. No. 6,243,483 to Petrou et al. (PII North America, Inc.) issued Jun. 5, 2001 shows a mapping system for automated pipeline surveillance. Satellite data is integrated with the pipeline data to produce a current pipeline map. The current pipeline map is then compared with a previous pipeline map to determine whether the route of the pipeline or a surrounding environment of the pipeline has changed.
U.S. Pat. No. 6,766,226 to Andersen issued Jul. 20, 2004 (Andersen Aeronautical Technologies) shows a method of monitoring utility lines with an aircraft using a dual sensor camera capable of concurrently capturing both thermal images and real time video images.
U.S. Pat. No. 7,184,072 to Loewen et al. issued Feb. 27, 2007 shows a system and apparatus for acquiring images of electric transmission lines using a fixed wing aircraft and an arrangement of at least one still camera. A laser altimeter or a combination of preset longitude/latitude coordinates, and a GPS unit supply continuous longitude/latitude coordinates for the aircraft location for comparison to preset coordinates.
U.S. Pat. No. 5,894,323 to Kain et al. (TASC, Inc.) issued Apr. 13, 1999 shows an airborne imaging system using global positioning system (GPS) and inertial measurement unit (IMU) data. The IMU provides data representative of the attitude of the camera. The claims require an inertial measurement unit (IMU) and are not an infringement issue.
United States Patent Application 20070061076 to Shulman published Mar. 15, 2007 shows a survey for detecting a changed condition. Real-time geographic images are memorialized in conjunction with GPS coordinates, and are stored in ESRI shape file format. Later, when the same geographic space is traversed from a moving vehicle equipped with a GPS, the memorialized images are played back by coordinating the GPS data. An observer traveling within the moving vehicle can compare the memorialized images with those being traversed in order to identify changed conditions.
United States Patent Application 20050007450 to Hill et al. published Jan. 13, 2005 shows a power line survey using an aerial craft, such as a helicopter, to capture continuous visual, spatial (GPS), and related physical data, and a method for parsing the data to create a stream for analysis.
The foregoing references generally measure attitude of the aircraft and GPS coordinates, and on-board software calculates aiming data for controlling the digital camera based on the line of sight of the platform. The automatic aiming is done in accordance with the pre-defined position of the electric line, and the position of the helicopter based on GPS and attitude. However, there is no teaching about how the automatic aiming is done. Consequently, there remains a need for a system that computes the shortest vector between the aircraft position and the pipeline based on the aircraft GPS and the a geolocation database, and then commands a stabilized camera system to point directly at the pipeline regardless of the aircraft position and orientation, automatically collecting NTSC or digital video of the entire right of way.